#include        <stdio.h>
#include        <stdlib.h>
#include        <unistd.h>
#include        <fcntl.h>

#define BUFFERSIZE      4096
#define COPYMODE        0644

void oops(char *, char *);

int main(int argc, char *argv[])
{
	int in_fd, out_fd, n_chars;
	char buf[BUFFERSIZE];
	if (argc != 3) {
		fprintf(stderr, "usage: %s source destination\n", *argv);
		exit(1);
	}

	if ((in_fd = open(argv[1], O_RDONLY)) == -1)//cannot open the copy text
		oops("Cannot open ", argv[1]);

	if ((out_fd = creat(argv[2], COPYMODE)) == -1)//cannot create new text
		oops("Cannot creat", argv[2]);

	while ((n_chars = read(in_fd, buf, BUFFERSIZE)) > 0)//read ok
		if (write(out_fd, buf, n_chars) != n_chars)//write error
			oops("Write error to ", argv[2]);
	if (n_chars == -1)//read error
		oops("Read error from ", argv[1]);


	if (close(in_fd) == -1 || close(out_fd) == -1)//close errror
		oops("Error closing files", "");
}

void oops(char *s1, char *s2)//just for print error
{
	fprintf(stderr, "Error: %s ", s1);
	perror(s2);
	exit(1);
}
